Active_model_serializers: has_one association not included in rendered json

[prrrnd]

Expected behavior vs actual behavior

Parking has_many :cars
Car has_one :driver

class ParkingSerializer < ActiveModel::Serializer
  attributes :id, :location
  has_many :cars
end

class CarSerializer < ActiveModel::Serializer
  attributes :id, :brand
  has_one :driver
end

class DriverSerializer < ActiveModel::Serializer
  attributes :id, :name
end

Expected
A driver nested under each car in the json when rendering a parking

Result
json with parking's attributes, cars, cars attributes except driver

Steps to reproduce

See serializers above

Controller:

# ...
def show
  @parking = Parking.find(params[:id])
  render json: @parking
end
# ...

Environment

ActiveModelSerializers Version 0.10.2
ruby 2.2.3p173 (2015-08-18 revision 51636) [x86_64-darwin15]
macOS Sierra
Rails 4.2.7.1

[beauby]

Json adapter?

[prrrnd]

@beauby I'm using the default one, :attributes
Also worth noting, 0.9.5 works fine, the issue appears when I upgrade to 0.10.2

[groyoh]

@prrrnd try:

render json: @parking, include: "*.*"

With 0.10, associations are included by default only for the first level. If you want to include deeper associations, you need to specify it with the include directive. In this case, include: "*.*" means include any association up to 2 levels. You may also use include: ** to include every level (not recommended) or be more specific include: "cars.driver".

[prrrnd]

@groyoh Thanks, I'll try that and report back.
Seems like your explanation could be part of the documentation, it's waiting for a PR.

[groyoh]

@prrrnd yeah the documentation is definitely lacking some love. If this was helpful for you, maybe you would kind enough to help us out with the doc :smile:

[prrrnd]

@groyoh The include directive definitely helped. I'll try to update the documentation in a PR.